U.S. patent application number 11/147171 was filed with the patent office on 2006-03-09 for robot control apparatus and control method thereof.
Invention is credited to Phil-joo Cho, Seung-won Yang.
Application Number | 20060049790 11/147171 |
Document ID | / |
Family ID | 35995544 |
Filed Date | 2006-03-09 |
United States Patent
Application |
20060049790 |
Kind Code |
A1 |
Yang; Seung-won ; et
al. |
March 9, 2006 |
ROBOT CONTROL APPARATUS AND CONTROL METHOD THEREOF
Abstract
A robot control apparatus to control an operation path of a
robot includes an interpolator including a rough interpolation
processor to output a rough velocity signal of no-acceleration and
no-deceleration according to input commands, a plurality of
acceleration/deceleration processors to receive the rough velocity
signal from the rough interpolation processor and to perform
acceleration and deceleration in sequence, and an inverse
kinematics processor to transform the velocity signal received from
the acceleration/deceleration processor into a joint velocity
signal for the robot, and a controller to control the robot
according to the accelerated/decelerated velocity signal received
from the interpolator. In a robot control apparatus and a control
method thereof, precision about an operation path of a robot is
improved.
Inventors: |
Yang; Seung-won; (Seoul,
KR) ; Cho; Phil-joo; (Suwon-si, KR) |
Correspondence
Address: |
STANZIONE & KIM, LLP
919 18TH STREET, N.W.
SUITE 440
WASHINGTON
DC
20006
US
|
Family ID: |
35995544 |
Appl. No.: |
11/147171 |
Filed: |
June 8, 2005 |
Current U.S.
Class: |
318/568.12 |
Current CPC
Class: |
G05B 2219/40488
20130101; B25J 9/1648 20130101 |
Class at
Publication: |
318/568.12 |
International
Class: |
B25J 5/00 20060101
B25J005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 7, 2004 |
KR |
2004-71259 |
Claims
1. A robot control apparatus to control an operation path of a
robot, the robot control apparatus comprising: an interpolator
comprising: a rough interpolation processor to output one or more
rough velocity signals according to input commands; a plurality of
acceleration/deceleration processors to receive corresponding ones
of the rough velocity signals from the rough interpolation
processor and to perform acceleration and deceleration processes in
sequence to output one or more velocity signals; and an inverse
kinematics processor to transform the one or more velocity signals
received from the plurality of acceleration/deceleration processors
into one or more joint velocity signals for the robot; and a
controller to control the robot on a basis of the joint velocity
signals received from the interpolator.
2. The robot control apparatus according to claim 1, wherein the
interpolator further comprises: a superposition processor to
superpose the respective joint velocity signals transformed by the
inverse kinematics processor.
3. The robot control apparatus according to claim 2, wherein the
superposition processor superposes a deceleration section and an
acceleration section of the respective joint velocity signals.
4. The robot control apparatus according to claim 1, wherein the
plurality of acceleration/deceleration processors comprises: a
first acceleration/deceleration processor; and a second
acceleration/deceleration processor.
5. The robot control apparatus according to claim 4, wherein the
one or more rough velocity signals comprises odd numbered rough
velocity signals and even numbered rough velocity signals, and the
first acceleration/deceleration processor performs the acceleration
and the deceleration processes in sequence with respect to the odd
numbered rough velocity signals received from the rough
interpolation processor, and the second acceleration/deceleration
processor performs the acceleration and the deceleration processes
in sequence with respect to the even numbered rough velocity
signals received from the rough interpolation processor.
6. The robot control apparatus according to claim 1, further
comprising: a planner to analyze the one or more input commands
about an operation of the robot and to output positioning
information to the interpolator.
7. The robot control apparatus according to claim 1, wherein the
one or more rough velocity signals are free of acceleration and
deceleration.
8. The robot control apparatus according to claim 1, wherein the
one or more rough velocity signals comprise a constant initial
velocity and a constant final velocity.
9. A robot control interpolator used with a robot control
apparatus, comprising: a first acceleration/deceleration processor
to receive a first rough velocity signal, and to perform
acceleration and deceleration processes to the first rough velocity
signal to provide a first velocity signal; a second
acceleration/deceleration processor to receive a second rough
velocity signal, and to perform acceleration and deceleration
processes to the second rough velocity signal to provide a second
velocity signal; and an inverse kinematics processor to transform
the velocity signals received from the first and second
acceleration/deceleration processors into first and second joint
velocity signals for a robot, respectively.
10. The robot control interpolator according to claim 9, further
comprising: a rough interpolation processor to output the first and
second rough velocity signals according to at least one input
command.
11. The robot control interpolator according to claim 9, further
comprising: a superposition processor to superpose the joint
velocity signals transformed by the inverse kinematics
processor.
12. The robot control interpolator according to claim 11, wherein
the superposition processor superposes a deceleration section and
an acceleration section of the respective joint velocity
signals.
13. The robot control interpolator according to claim 11, wherein
the first joint velocity signal comprises a first acceleration
section and a first deceleration section, the second joint velocity
signal comprises a second acceleration section and a second
deceleration section, and the superposition processor superposes
the first acceleration section of the first joint velocity signal
and the second acceleration section of the second joint velocity
signal.
14. The robot control interpolator according to claim 11, wherein
the first rough velocity signal comprises odd numbered rough
velocity signals, the second rough velocity signal comprises even
numbered rough velocity signals, and the first
acceleration/deceleration processor performs the acceleration and
the deceleration processes in sequence with respect to the odd
numbered rough velocity signals received from the rough
interpolation processor, and The second acceleration/deceleration
processor performs the acceleration and the deceleration processes
in sequence with respect to the even numbered rough velocity
signals received from the rough interpolation processor.
15. The robot control interpolator according to claim 9, wherein
the first joint velocity signal comprises a deceleration section,
the second joint velocity signal comprises an acceleration section,
and start points of the deceleration section of the first joint
velocity signal and the acceleration section of the second joint
velocity signal are controlled to match.
16. A control method of a robot control apparatus to control an
operation path of a robot, the control method comprising:
outputting one or more rough velocity signals according to one or
more input commands; allowing a plurality of
acceleration/deceleration processors to receive the one or more
rough velocity signals and to perform acceleration and deceleration
processes in sequence, and to output one or more velocity signals;
transforming the one or more velocity signals received from the
plurality of acceleration/deceleration processors into a joint
velocity signal for the robot; and controlling the robot according
to the joint velocity signal.
17. The control method according to claim 16, wherein the joint
velocity signal comprises first and second joint velocity signals
corresponding to the one or more velocity signals, and the
transforming the one or more velocity signals comprises superposing
the first and second joint velocity signals as the joint velocity
signal.
18. The control method according to claim 16, wherein the allowing
of the plurality of acceleration/deceleration processors to receive
the one or more rough velocity signals comprises: allowing the
first acceleration/deceleration processor to perform the
acceleration and the deceleration processes in sequence with
respect to odd numbered rough velocity signals, and allowing the
second acceleration/deceleration processor to perform the
acceleration and the deceleration processes in sequence with
respect to even numbered rough velocity signals.
19. The control method according to claim 16, wherein the rough
velocity signal is free of acceleration and deceleration.
20. The control method according to claim 16, wherein the rough
velocity signal comprises a constant initial velocity and a
constant final velocity.
21. A method to control an operation path of a robot, the control
method comprising: receiving a first rough velocity signal in a
first acceleration and/or deceleration processor; performing
acceleration and/or deceleration processes to the first rough
velocity signal to provide a first velocity signal; receiving a
second rough velocity signal in a second acceleration and/or
deceleration processor; performing acceleration and/or deceleration
processes to the second rough velocity signal to provide a second
velocity signal; and transforming the first and second velocity
signals into first and second joint velocity signals for a robot,
respectively.
22. The method according to claim 21, further comprising:
superposing a deceleration section of the first joint velocity
signal over an acceleration section of the second joint velocity
signal.
23. The method according to claim 21, wherein: the operation of
performing acceleration and deceleration processes to the first
rough velocity signal comprises, determining whether a number
associated with the first rough velocity signal is an odd number,
and if so, performing the first acceleration and/or deceleration
processes using a first acceleration/deceleration processor to
provide the first velocity signal; and the operation of performing
acceleration and/or deceleration processes to the second rough
velocity signal comprises, determining whether a number associated
with the second rough velocity signal is an even number, and if so,
performing the second acceleration and/or deceleration processes
using a second acceleration/deceleration processor to provide the
second velocity signal.
24. The method according to claim 21, wherein the first joint
velocity signal comprises a first acceleration section and a first
deceleration section, the second joint velocity signal comprises a
second acceleration section and a second deceleration section, and
wherein the method further comprises superposing the first
acceleration section of the first joint velocity signal and the
second acceleration section of the second joint velocity
signal.
25. The method according to claim 21, wherein the first rough
velocity signal comprises a linear velocity, and wherein the second
rough velocity signal comprises a circumferential angular velocity.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Application No. 2004-71259, filed on Sep. 7, 2004, in the Korean
Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety and by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present general inventive concept relates to a robot
control apparatus and a control method thereof, and more
particularly, to a robot control apparatus and a control method
thereof, which comprise a dual acceleration/deceleration processor
to control an operation path of a robot.
[0004] 2. Description of the Related Art
[0005] Generally, a robot control apparatus comprises an
interpolator to keep an operation path of an industrial robot or
the like, and to make the robot operate continuously between
respective path modes.
[0006] Interpolation can be achieved by a circuit or a software
module, which calculates disposition of respective joints provided
in the robot at every control period so as to control the robot as
a user wants, according to various path modes such as a linear
path, a circular path, and a point-to-point path. Such an
interpolator comprises an acceleration/deceleration filter, such as
a low pass filter, to accelerate or decelerate a motor provided in
a joint of the robot.
[0007] Such a conventional robot control apparatus is disclosed in
Korean Patent Application No. 1997-80191 (U.S. Pat. No. 6,046,564),
titled "PATH PLANNING APPARATUS AND METHOD FOR ROBOTS." The
conventional path planning apparatus for controlling a robot
comprises an interpolator formed by a single low pass filter which
receives a velocity profile Va calculated on a basis of a target
positioning signal and performs a path interpolation to output a
smoothed velocity profile Vb, and a servo controller which receives
output of the interpolator and controls acceleration and
deceleration of a servo motor. Thus, the conventional path planning
apparatus for controlling the robot smoothes the operation of the
servo motor through the interpolator formed by the single low pass
filter, thereby decreasing damage in the robot.
[0008] However, in the conventional robot control apparatus, the
interpolator employs the single acceleration/deceleration filter
such as the low pass filter, so that a relatively large path error
arises with respect to an input command path when the robot
continuously operates along various path modes such as the linear
path and the circular path.
[0009] FIG. 1 is a schematic representation of a set of operations
of a conventional robot control apparatus, wherein the conventional
robot control apparatus controls a robot to operate along a linear
path LP and a circular path CP in sequence.
[0010] First, a linear velocity .DELTA.X and a circumferential
angular velocity .DELTA..psi. are calculated by detecting a
positioning signal from an input linear path LP and an input
circular path CP. In the case of the linear path LP, the linear
velocity .DELTA.X can be used as an input value of an
acceleration/deceleration filter 120. In the case of the circular
path CP, the circumferential angular velocity .DELTA..psi. can be
used as the input value of the acceleration/deceleration filter
120. However, the linear velocity .DELTA.X and the circumferential
angular velocity .DELTA..psi. are different in a dimension, so the
linear velocity .DELTA.X and the circumferential angular velocity
.DELTA..psi. are transformed into joint velocities (.DELTA..theta.,
.DELTA..theta.') through an inverse kinematics process before being
inputted to the acceleration/deceleration filter 120 so as to
prevent the input values that are different in dimension from
interacting with each other in the acceleration/deceleration filter
120. Thus, the transformed joint velocities (.DELTA..theta.,
.DELTA..theta.') are used as the input values of the
acceleration/deceleration filter 120, in sequence.
[0011] As described above, the conventional robot control apparatus
comprises the single acceleration/deceleration filter 120, so the
inverse kinematics process (refer to equation 1) should be
performed prior to the acceleration/deceleration filter 120 in the
case of a continuous operation between the different path modes. At
this time, the linear velocity .DELTA.X is nonlinearly related to
the joint velocity .DELTA..theta. so a relatively large path error
arises during an acceleration/deceleration process. For example,
the joint velocity .DELTA..theta. obtained by the inverse
kinematics process (refer to equation 1) is accelerated/decelerated
by the acceleration/deceleration filter 120, and then a forward
kinematics process (refer to equation 2) is used to check whether
the accelerated/decelerated joint velocity .DELTA..theta. is equal
to the linear velocity .DELTA.X. As a result of the check, a
relatively large path error arises with respect to the input
command path. .DELTA..theta.=J.sup.-1(.theta.).DELTA.X (equation 1)
.DELTA.X=J(.theta.).DELTA..theta. (equation 2)
[0012] Where J(.theta.) is a Jacobian matrix.
[0013] Thus, the conventional robot control apparatus is in need of
an ability to operate the robot without a relatively large path
error due to the single acceleration/deceleration filter with
respect to an actual path.
SUMMARY OF THE INVENTION
[0014] The present general inventive concept provides a robot
control apparatus and a control method thereof, which are improved
in precision with respect to an operation path of a robot.
[0015] Additional aspects and advantages of the present general
inventive concept will be set forth in part in the description
which follows and, in part, will be obvious from the description,
or may be learned by practice of the general inventive concept.
[0016] The foregoing and/or other aspects of the present general
inventive concept may be achieved by providing a robot control
apparatus to control an operation path of a robot, the robot
control apparatus comprising an interpolator having a rough
interpolation processor to output a rough velocity signal of
no-acceleration and no-deceleration according to one or more input
commands, a plurality of acceleration/deceleration processors to
receive the rough velocity signal from the rough interpolation
processor and to perform acceleration and deceleration in sequence,
and an inverse kinematics processor to transform velocity signals
received from the acceleration/deceleration processors into joint
velocity signals for the robot, and a controller to control the
robot on a basis of the joint velocity signals received from the
interpolator.
[0017] The interpolator may further comprise a superposition
processor to superpose the respective joint velocity signals
transformed by the inverse kinematics processor.
[0018] The superposition processor may superpose a deceleration
section and an acceleration section of the respective joint
velocity signals.
[0019] The plurality of acceleration/deceleration processors may
comprise a first acceleration/deceleration processor and a second
acceleration/deceleration processor.
[0020] The first acceleration/deceleration processor may perform
the acceleration and the deceleration in sequence on a basis of odd
numbered rough velocity signals received from the rough
interpolation processor, and the second acceleration/deceleration
processor may perform the acceleration and the deceleration in
sequence on a basis of even numbered rough velocity signals
received from the rough interpolation processor.
[0021] The robot control apparatus may further comprise a planner
to analyze the one or more input commands about operation of the
robot and to output positioning information to the
interpolator.
[0022] The foregoing and/or other aspects of the present general
inventive concept may also be achieved by providing a control
method of a robot control apparatus to control an operation path of
a robot, the control method comprising outputting a rough velocity
signal of no-acceleration and no-deceleration according to input
commands, allowing a plurality of acceleration/deceleration
processors to receive the rough velocity signal and to perform
acceleration and deceleration in sequence, transforming velocity
signals received from the acceleration/deceleration processors into
joint velocity signals for the robot, and controlling the robot on
a basis of the joint velocity signal.
[0023] The control method may further comprise superposing the
respective joint velocity signals.
[0024] The plurality of acceleration/deceleration processors may
comprise a first acceleration/deceleration processor and a second
acceleration/deceleration processor, and the control method may
further comprise allowing the first acceleration/deceleration
processor to perform the acceleration and the deceleration in
sequence on a basis of odd numbered rough velocity signals, and
allowing the second acceleration/deceleration processor to perform
the acceleration and the deceleration in sequence on a basis of
even numbered rough velocity signals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and/or other aspects and advantages of the present
general inventive concept will become apparent and more readily
appreciated from the following description of the embodiments,
taken in conjunction with the accompanying drawings of which:
[0026] FIG. 1 is a schematic representation of a set of operations
of a conventional robot control apparatus;
[0027] FIG. 2 is a block diagram of a robot control apparatus
according to an embodiment of the present general inventive
concept;
[0028] FIG. 3 is a schematic representation of an exemplary path
along which the robot control apparatus of FIG. 2 moves;
[0029] FIG. 4 is a schematic representation of a process of
applying a robot control apparatus to the path of FIG. 3 according
to an embodiment of the present general inventive concept;
[0030] FIGS. 5A and 5B are schematic representations of actual
paths obtained by applying the robot control apparatus of FIG. 2
and a conventional robot control apparatus to the path of FIG. 3 on
a basis of a forward kinematics, respectively;
[0031] FIGS. 6A and 6B are schematic representations of path errors
of the paths of FIGS. 5A and 5B, respectively; and
[0032] FIG. 7 is a flowchart illustrating a method of a robot
control apparatus according to an embodiment of the present general
inventive concept.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Reference will now be made in detail to the embodiments of
the present general inventive concept, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to like elements throughout. The embodiments are
described below in order to explain the present general inventive
concept by referring to the figures.
[0034] As shown in FIG. 2, a robot control apparatus 1 according to
an embodiment of the present general inventive concept comprises an
interpolator 20 to keep an operation path to control a robot (not
shown) to move along the operation path and to make the robot
operate continuously between respective path modes, and a
controller 30 to control the robot on a basis of a signal received
from the interpolator 20. Further, the robot control apparatus 1
according to an embodiment of the present general inventive concept
comprises a planner 10 to analyze an input command about an
operation of the robot and to output positioning information to the
interpolator 20.
[0035] The planner 10 receives the input command given by a user
with regard to the operation path of the robot, and analyzes the
input command, thereby transmitting the positioning information or
the like to the interpolator 20.
[0036] The interpolator 20 comprises a rough interpolation
processor 21 to output a rough velocity signal of no-acceleration
and no-deceleration according to the positioning information and/or
the input command, a plurality of acceleration/deceleration
processors 23 and 25 to receive the rough velocity signal of the
rough interpolation processor 21 and to perform acceleration and/or
deceleration processes (acceleration and deceleration) in sequence,
and an inverse kinematics processor 27 to transform velocity
signals received from the acceleration/deceleration processors 23
and 25 into joint velocity signals for the robot. Further, the
interpolator 20 may comprise a superposition processor 29 to
superpose the respective joint velocity signals received by the
inverse kinematics processor 27.
[0037] The rough interpolation processor 21 receives the
positioning information about the operation path of the robot from
the planner 10, and outputs the rough velocity signal to the
acceleration/deceleration processors 23 and 25. The rough velocity
signal outputted from the rough interpolation processor 21 contains
a velocity profile having a constant initial velocity and a
constant final velocity. Therefore, if the rough velocity signal is
directly transmitted to the controller 30, a driving motor 40
provided in a joint of the robot may be damaged.
[0038] Each of the acceleration/deceleration processors 23 and 25
may be embodied as an acceleration/deceleration filter such as a
low pass filter to accelerate and/or decelerate the driving motor
40 provided in the joint of the robot. However, the
acceleration/deceleration processors 23 and 25 are not limited to
acceleration/deceleration filters, and may comprise various
software programs or the like formulated to accelerate or
decelerate the driving motor 40 provided in the joint of the robot.
The plurality of acceleration/deceleration processors 23 and 25
comprises a first acceleration/deceleration processor 23 and a
second acceleration/deceleration processor 25. The plurality of
acceleration/deceleration processors 23 and 25 is not limited to
one pair of acceleration/deceleration processors (the first
acceleration/deceleration processor 23 and the second
acceleration/deceleration processor 25), and may comprise
additional acceleration/deceleration processors.
[0039] The first acceleration/deceleration processor 23 performs
the acceleration and deceleration in sequence with respect to odd
numbered rough velocity signals received from the rough
interpolation processor 21. That is, the first
acceleration/deceleration processor 23 sequentially processes the
odd numbered rough velocity signals, such as first, third and fifth
rough velocity signals, and so on, received from the rough
interpolation processor 21, and then transmits them to the inverse
kinematics processor 27.
[0040] The second acceleration/deceleration processor 25 performs
the acceleration and deceleration in sequence with respect to even
numbered rough velocity signals received from the rough
interpolation processor 21. That is, the second
acceleration/deceleration processor 25 sequentially processes the
even numbered rough velocity signals, such as second, fourth and
sixth rough velocity signals, and so on, received from the rough
interpolation processor 21, and then transmits them to the inverse
kinematics processor 27.
[0041] The inverse kinematics processor 27 transforms accelerated
and decelerated velocity signals received from the first and second
acceleration/deceleration processors 23 and 25 into the joint
velocity signal of the robot. That is, the inverse kinematics
processor 27 transforms the velocity signals about various path
modes, such as a linear path, a circular path, and/or a
point-to-point path, as a user wants, into the joint velocity
signal according to the above-mentioned equation 1, and then
transmits the transformed joint velocity signal to the
superposition processor 29. Here, the inverse kinematics processor
27 can be formed as a pair corresponding to the first and second
acceleration/deceleration processors 23 and 25, or formed as a
single inverse kinematics processor, thereby transforming the
velocity signal transmitted from the first and second
acceleration/deceleration processors 23 and 25 into the joint
velocity signal of the robot. Further, the inverse kinematics
processor 27 can be configured as hardware to process the
accelerated/decelerated velocity signal through an inverse
kinematics process, and can be configured as software provided in
the interpolator 20 to process the accelerated/decelerated velocity
signal through the inverse kinematics.
[0042] The superposition processor 29 superposes the joint velocity
signals transmitted from the inverse kinematics processor 27, in
sequence. The superposition processor 29 superposes a deceleration
section of a previously transmitted joint velocity signal and an
acceleration section of a subsequently transmitted joint velocity
signal. For example, the superposition processor 29 superposes the
joint velocity signals to match a start point of the deceleration
section of the previously transmitted joint velocity signal with a
start point of the acceleration section of the subsequently
transmitted joint velocity signal. The superposition processor 29
can superpose the joint velocity signals without being limited to
the foregoing method, and may have various alternative methods. The
superposition processor 29 can be configured as hardware to
superpose the joint velocity signals processed through the inverse
kinematics, and/or can be configured as software provided in the
interpolator 20 to superpose the joint velocity signals processed
through the inverse kinematics.
[0043] The controller 30 controls the driving motor 40 of the robot
according to a superposed velocity signal received from the
superposition processor 29.
[0044] With this configuration, operations of the robot control
apparatus 1 of FIG. 2 according to an embodiment of the present
general inventive concept will be described with reference to FIGS.
3 through 7.
[0045] FIG. 3 is a schematic representation of an exemplary path
along with the robot control apparatus 1 of FIG. 2 is supposed to
move. As shown in FIGS. 2 and 3, the path (refer to a dotted line
of FIG. 3) provided to test the robot control apparatus alternately
comprises the linear path (LP1:P1-P2, LP2:P3-P4, LP3:P5-P6,
LP4:P7-P1) and the circular path (CP1:P2-P3, CP2:P4-P5,
CP3:P6-P7).
[0046] FIG. 4 is a schematic representation of a process of
applying a robot control apparatus to the path of FIG. 3 according
to an embodiment of the present general inventive concept. FIG. 7
is a flowchart illustrating a method of a robot control apparatus
according to an embodiment of the present general inventive
concept.
[0047] At operation S1, the planner 10 outputs the positioning
information corresponding to the input command given by a user or
the like. At operation S3, the rough interpolation processor 21
outputs a first rough linear velocity .DELTA.X1, a rough
circumferential angular velocity .DELTA..psi.1, a second rough
linear velocity .DELTA.X2, or the like corresponding to a first
linear path LP1, a circular path CP1, and a second linear path LP2.
At operation S5, it is checked whether the first rough linear
velocity .DELTA.X1, the rough circumferential angular velocity
.DELTA..psi.1, and the second rough linear velocity .DELTA.X2
outputted from the rough interpolation processor 21 are
odd-numbered or even-numbered. At operation S7, the odd-numbered
rough linear velocities .DELTA.X1 and .DELTA.X2 are transmitted to
the first acceleration/deceleration processor 23 and then
accelerated/decelerated. At operation S9, the even-numbered rough
circumferential angular velocity .DELTA..psi.1 is transmitted to
the second acceleration/deceleration processor 25 and then
accelerated/decelerated. At operation S11, the
accelerated/decelerated linear velocity and the
accelerated/decelerated circumferential angular velocity are
transformed by the inverse kinematics processor 27 into the
respective joint velocities .DELTA..theta.1, .DELTA..theta.2, and
.DELTA..theta.3. At operation S13, the transformed joint velocities
.DELTA..psi.1, .DELTA..psi.2, and .DELTA..psi.3 are superposed and
transformed by the superposition processor 29 into a superposition
velocity .DELTA..psi.t. At operation S15, the superposition
velocity .DELTA..theta.t is transmitted to the controller 30,
thereby controlling the driving motor 40.
[0048] FIGS. 5A and 5B are schematic representations of actual
paths obtained by applying the robot control apparatus of FIG. 2
and a conventional robot control apparatus having a single
acceleration/deceleration filter to the paths (refer to dotted
lines of FIGS. 3, 5A and 5B) on a basis of a forward kinematics,
respectively. As shown therein, FIG. 5A is a schematic
representation of a path of an actual result obtained by the robot
control apparatus of FIG. 2 to perform the foregoing operation
(refer to a solid line of FIG. 5A). FIG. 5B is a schematic
representation of a path of an actual result obtained by the
conventional robot control apparatus comprising the single
acceleration filter to perform the inverse kinematics before a
process of the acceleration/deceleration filter (refer to a solid
line of FIG. 5B). FIGS. 6A and 6B are schematic representations of
path errors of the paths of FIGS. 5A and 5B, respectively. The test
illustrated in FIGS. 5A, 5B, 6A and 6B was performed under the
conditions of a path moving velocity of 1000 millimeters per second
(mm/sec), an acceleration/deceleration time of 320 milliseconds
(msec), and an interpolation period of 4 msec. As shown in FIGS. 6A
and 6B, the robot control apparatus 1 according to an embodiment of
the present general inventive concept has a maximum path error of 2
mm, while the conventional robot control apparatus has a maximum
path error of 22 mm. The robot control apparatus 1 according to an
embodiment of the present general inventive concept enhances
precision about an operation path of a robot as compared with a
conventional robot control apparatus.
[0049] A robot control apparatus according to an embodiment of the
present general inventive concept comprises a plurality of
acceleration/deceleration processors to process an
accelerated/decelerated velocity signal on a basis of inverse
kinematics, thereby enhancing the precision of an operation path of
a robot joint.
[0050] As described above, the present general inventive concept
provides a robot control apparatus and a control method thereof,
which is improved in precision about an operation path of a
robot.
[0051] Although a few embodiments of the present general inventive
concept have been shown and described, it will be appreciated by
those skilled in the art that changes may be made in these
embodiments without departing from the principles and spirit of the
general inventive concept, the scope of which is defined in the
appended claims and their equivalents.
* * * * *